JPS589955B2 - Key signal generator for electronic musical instruments - Google Patents

Description

[Detailed description of the invention] The present invention relates to a key signal generating device for an electronic musical instrument.

2. Description of the Related Art Conventionally, it has been considered to obtain a volume or tone depending on the touch of a key in an electronic musical instrument.

In this case, the key signal is obtained by detecting the key depression speed, or the pressing force is obtained as an electrical signal using a piezoelectric element.
By using one of these alone, the volume, tone, etc. were controlled.

By the way, if one or the other is used, subtle key movements during performance cannot be accurately expressed as volume or tone.

That is, even if the speed at which the key is pressed is the same, the volume and tone should be different depending on whether the key is pressed forcefully or with less force, but they end up being the same.

Furthermore, even when the pressing force is the same, there should be a change in the pressing speed.

That is, the movement of a key has two elements: pressing speed and pressing force, and the movement cannot be expressed accurately using only one of them.

The present invention aims to obtain a key signal that can simultaneously express two elements of a key, and includes a speed detection circuit 6 that detects the pressing speed of a key, and a pressing force that detects the pressing force of the key. A detection circuit 7, a control circuit 8 that controls the output signal of the speed detection circuit 6 based on the output signal of the pressing force detection circuit 7, and an envelope addition circuit 9 that adds an envelope to the output signal from the control circuit 8. Become,
The speed detection circuit 6 includes a key switch 6a that is activated when a key is pressed, and a first capacitor 6b that is discharged or charged when the key is pressed.
consists of a piezoelectric element 7a that is struck when a key is pressed, and the control circuit 8 is controlled by the potential of the first capacitor 6b, and includes a first semiconductor element 8 whose one end is connected to a power supply.
a and a second semiconductor element 8a connected in series thereto and controlled by the output voltage of the piezoelectric element 7a, and the envelope adding circuit 9 connects the output line l of the second semiconductor element 8b to its output terminal. 14, a second capacitor 9a, a resistor 9b, and a second key switch 15 interlocked with the key switch 6a are provided in parallel between the output line l and the ground point, and the envelope The key signal is obtained from the output terminal 14 of the additional circuit 9.

Next, embodiments of the present invention will be described with reference to the attached drawings.

FIG. 1 shows a block diagram showing an embodiment of the present invention, in which 1 is a sound source signal oscillator, 2 is a gate circuit, 3 is a filter, 4 is an amplifier, 5 is a speaker, and 6 is a key press speed detection device. A speed detection circuit, 7 is a pressing force detection circuit that detects the pressing force of the key, 8 is a control circuit that controls the output signal of the speed detection circuit 6 based on the output signal of the pressing force detection circuit 7, and the output key signal The envelope signal forming circuit 9 is controlled by the envelope signal forming circuit 9, and the gate circuit 2 is controlled by the envelope signal obtained from the envelope signal, so that the sound volume is changed according to two factors, namely, speed and pressing force.

FIG. 2 shows an example of a specific implementation of the present invention, in which the speed detection circuit 6 consists of a key switch 6a that is opened when a key is pressed, and a capacitor 6b that starts charging when the key switch 6a is opened. The pressing force detection circuit 7 is made up of a piezoelectric element 7a that is struck when a key is pressed, and the control circuit 8 is made up of first and second semiconductor elements 8 made of transistors connected in series.
A, 8b, and a resistor 1 is connected to the base of the transistor 8a and the terminal of the power supply 10 side of the capacitor 6b of the speed detection circuit 6.
1, and one pole of the piezoelectric element constituting the pressing force detection circuit 7 was connected to the base of the transistor 8b via the diode 12.

The emitter of transistor 8b is diode 1.
3 to the envelope signal forming circuit 9.

The envelope signal forming circuit 9 has the anode of the diode 13 directly connected to the output terminal 14 and grounded via a parallel capacitor 9a and a resistor 9b.
c and grounded via the normally closed key switch 15.

The piezoelectric elements constituting the helmet, the key switches 6a and 15, and the pressing force detection circuit 7 are such that when the key a is pressed as shown in the third figure, the key switches 6a and 15 are first opened, and then the key a is opened. The piezoelectric element 7a is struck by the hammer b at the position where the depression is completed.

Thus, if you press key a with the current force, key switch 6a
, 15 are opened at the same time, and when the key switch 6a is opened, charging of the capacitor 6b is started via the resistor 16.

When the piezoelectric element 7a is struck by the hammer b during the process of the transistor constituting the semiconductor element 8a gradually changing from a conductive state to a cut-off state, a pulse is generated, which is added to the transistor constituting the semiconductor element 8b, and the transistor 8a , 8b are turned on (key signal) is charged to the capacitor 9a through the diode 13.

If a pulse is output from the piezoelectric element 7a in a state where the capacitor 6b is not sufficiently charged, a voltage close to the power supply voltage +■ is applied to the semiconductor element 8b.

When the pulse of the piezoelectric element 7a is thick, that is, when the key is pressed forcefully, the semiconductor element 8b becomes almost completely conductive, so that the capacitor 9a is charged to a value close to +V.

Conversely, if the pulse is small, the degree of opening of the semiconductor element 8b is small, so that the capacitor 9a is charged to a small voltage.

Furthermore, if the speed of the key is slow, the degree of opening of the semiconductor element 8a is small, so a low voltage is applied to the semiconductor element 8b.

At this voltage, a key signal corresponding to the output pulse of the piezoelectric element 7 is further obtained, and the capacitor 9a is charged.

In this way, the capacitor 9 of the envelope signal forming circuit 9
A is charged depending on the speed and pressing force of the key a, and is thereafter discharged through the resistor 9b, so that an envelope signal corresponding to the speed and pressing force of the key a is obtained at the output terminal.

Next, when the key a is released, the key switch 6a+15 is closed, the capacitors 6b and 9a are discharged, the envelope signal disappears, a damper effect is obtained, and the next signal is prepared.

Note that the key signal obtained in this way is not limited to being used to form an envelope signal, but can also be used to control the sound source signal oscillator 1 gate circuit 2, tone circuit 3, etc. via other control circuits. You can also do it.

In this way, according to the present invention, the speed and force of pressing the key are detected by the speed detection circuit and the force detection circuit, and the output signal of the rain detection circuit is used to generate a key signal corresponding to the speed and force of the key. As a result, it is possible to obtain musical tones that change in various ways according to the touch of a key, and a damper effect can be obtained when the key is released.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an example of an embodiment of the present invention, FIG. 2 is a specific circuit diagram of the main part thereof, and FIG. 3 is a cutaway side view of the key and key switch portion. 6... Speed detection circuit, 7... Pressing force detection circuit, 8... Control circuit, a... key, 6a... key Switch, 6b...Capacitor, 8a, sb...Semiconductor element, 9
...Envelope addition circuit.

Claims (1)

[Claims] 1. A speed detection circuit 6 that detects the pressing speed of a key, a pressing force detection circuit 7 that detects the pressing force of the key, and an output signal of the pressing force detecting circuit 7 to control the output signal of the speed detecting circuit 6. It consists of a control circuit 8 and an envelope adding circuit 9 that adds an envelope to the output signal from the control circuit 8, and the speed detection circuit 6 has a key switch 6a that is activated when a key is pressed and a discharge that occurs when the key is pressed. or a first capacitor 6b that is charged, the pressing force detection circuit 7 is composed of a piezoelectric element 7a that is struck as a key is pressed, and the control circuit 8 is controlled by the potential of the first capacitor 6b. and one end connected to the power supply.
and a second semiconductor element 8b connected in series with the semiconductor element 8a and controlled by the output voltage of the piezoelectric element 7a, and the envelope adding circuit 9 connects the output line l of the second semiconductor element 8b. A second capacitor 9a, a resistor 9b, and a second key switch 15 interlocked with the key switch 6a are provided in parallel between the output terminal 14 and the ground point. , a key signal generating device for an electronic musical instrument, which obtains a key signal from the output terminal 14 of the envelope adding circuit 9.